A multi-stage optical amplifier that has an optical fiber with a first length
of
amplifier fiber and a second length of amplifier fiber. The optical fiber is configured
to be coupled to a signal source that produces at least a signal wavelength s
and a pump source that produces a pump wavelength p. Pump wavelength
p is less than signal wavelength s. Signal
input, signal output and pump input ports are each coupled to the optical fiber.
A first lossy member is coupled to the optical fiber and positioned between the
first and second lengths of amplifier fiber. A pump shunt is coupled to the signal
input port and the signal output port.